Simplifying and interpreting two-tone measurements

• Published in: IEEE transactions on microwave theory and techniques Vol. 52; no. 11; pp. 2576 - 2584
• Main Authors: Remley, K.A., Williams, D.F., Schreurs, D.M.M.-P., Wood, J.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.11.2004; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Bandwidth; Baseband; Circuits; Distortion measurement; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; Frequency measurement; Gain measurement; Gain modulation; Instruments; intermodulation (IM) distortion; large-signal network analyzer; memory effects; nonlinear vector network analyzer (NVNA); Phase measurement; Power harmonic filters; Radiofrequency amplifiers; Theoretical study. Circuits analysis and design; two-tone measurements; Network analyzer; intermodulation (IM) distortion; Amplifier; nonlinear vector network analyzer (NVNA); Non linear circuit; memory effects; Gain modulation; Microwave circuit; large-signal network analyzer; Intermodulation; two-tone measurements; Memory effect; Signal distortion
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2004.837195

We develop a mathematical description of the response of weakly nonlinear systems to second-order memory mechanisms. Our description is based on a time-varying gain-modulation function. We show that intermodulation (IM) products arising from interactions at baseband have phase symmetries different from both interactions at second harmonic frequencies and gain compression and, thus, may be readily distinguished through measurement. We also demonstrate a technique for measuring and aligning the phase of IM products outside the measurement bandwidth of our instrumentation to identify contributions to memory with broad frequency response.